System of making observations and directing gun fire



l Feb. 12, 1935. w. i-. MURPHY .SYSTEM OF MAKING OBSERVATIONSAND DIRECTING GUN FIRE FiledAug; 21, 1954 4 sheets-sheet 1 Feb. l2, 1935.

w. H. MURPHY 1,990,494

SYSTEM OF MAKING OBSERVATIONS #AND DIRECTING GUN FIRE med Aug. 21, 1934Y 4 sheets-sheet 2 rraxvve/s Feb, 12, 1935. w. H. MURPHY i, 1,990,494

SYSTEMl OF MAKING OBSERVATIONS AND DIRECTING GUN FIRE Filed Aug. 21, 1934 4 Sheets-Sheet 3 frronylys Feb. 12, 1935. w H MLRPHY 1,990,494

SYSTEM OF MAKING OBSERVATIONS AND DIRCTING GUN FIRE Filed Aug. 2l, 1954 4 Sheets-Sheet 4 FAG. .9.

I/I//LL/AM /71 MURPHY 57%@ Patented Feb. 121, 1935 l DIRECTINQ GIINFIRE ,l

error; ti.. f. M

Wh n the trace Aof the upper antenna seetion extlyu abovethe tarfg'get,` theY operator muet vbe trahs'initte'rwiththe result that the ,I dectbnL ndeiyobtainsa'truepearing on the tag'e'tfrathr'than en' thel -airplaneor the transmtter of radio wave energy.v

apparatus; leated" at a' Vantage point, for eX-' L aniple, "on'l an aircraft Wherebyan observeren the craft and visa'lrange of an' object such as a target may'tranemit'isinals under certain conditions'in aecorda'nee'withthe 'principlesotthe inventionl'to directinlfindingstatins to enabley saidst'ationsto.v obtainbearing's on thevtarget and then determine its range and Aposition by known meth'ods. 4The' ,condtionsvarer satsed ,y Wlieiithe radio apparatus is iprovided with a radiating antenna which may be visually aligned.v with 1ongtudina1axsm at plane passing tbmugh theobiet or target,and` the pointmf` l target.'A It is"at this instant'that the radio signal 30'V 1 Tleprehseiit invention employs radio signaling 3.5""

Y oizervatifanf Taamanneir f aligning.l antenna l. v nd'the ai e and target depends upon the character of an- 50 n tenna ueed. Forezample,. a rigid dipole radiator anbraten@ ma'be emplcyed,- iifwl'iih'case`meansv are Vitzrovicleil'to couple. asighting, element. inoperative relation .in a given plane therewith throughout the range Inaccordance withv the theory of the presentinvention`,"said rela'-Y of adjustment of the device.

tion must be established and maintained while transmitting signals to one or morel direction finding stations.

where the craft is equipped'witn a trailing' antemia, the craft may be maneuvered .to-.es-

tablish the position of alignmentA of the optical axis of a sighting device withtlie eiective portion of such an antenna. To determine the moment of alignment, the observer sights along the upper or eifective part of the antenna,` or parallel thereto, and when it is observed that the' said upper part of the antenna has itslong'itu'- dinal axis in optical alignment with the target, and in a plane passing verticallythrough observation point'and target, at the instant such alignment is established a signal is transmittedy to be picked up at the direction finding stations. In practice a warning signal or signals would be sent so that the vdirection finding stations wouldv be on the alert to vcatch the succession'ofwsignals which .would .becontinued forl such interval as the condition Aof lalignment couldv be maintained. The resultf is that a direction finder or plurality of direction nders' may be used to obtain a bearing or Vbearings on 'the target, and not on the aircraft, during the interval of such alignment. Two direction, finders located on a base line may be kused to locate the range and position of the target which information is then communicatedL to the battery stations.

The mode vof operation-and certain preferred embodiments ofthe, invention. willnow be described with refe ings, vin which:

. Fig.l 1 shows an arrangement ofcontrol or direction nding stationsv relation to an observing aircraft, a target and a gun enplacement;

Fig. 2 depictsron aman Surface projection "theA position of the, direction finders on,a given base line in relation .to a target andgun emplacement,

giving one positionof the observing aicraft relative to the target; v

Fig. 3 shows 4a preferred form of rigidantenna mounted on an airplane fuselage andoperatively coupled` to -a radio transmitter, together withA mechanical means for maintaining the antennaV in parallelism with a sighting device;

Fig. llshows an alternative form of rigid antenna operative with a radio transmitter and" means for maintaining with a sighting device; f

Fig. 5 is a view similar toFig. 1 in which 'the observing aircraft is equipped with a trailing antenna;

the same in parallelism Fig. 6 shows a trailing antenna attached to anv` airplane in level flight to aid in visualizing the effective energy radiating portionA of this type of antenna; y j

Fig. 7 shows a sighting device for use with such a trailing antennawith` a calibrated speed sca-le attached;A

Figs. 8, 9, 10, 11 and 12 show a seriesncifv diagrams" rence to the accompanying draw-V to assist in demonstratingl the theory of the invention.

Referring to Fig. 8 of the drawings, assume that a dipole antenna, or a quarter wave length antenna, is located at an elevated point A, for example in an airplane; assume that C is the point or trace on the horizontal-plane at which the*y antenna, if extended-theoretically,-would cut the horizontal plane; that O is the vertical projection of the center of the dipole, and that B is a point on the horizontal plane at which a direction nderislocated. I'f'a is the vertical angle at point `Cy between the horizontal OC and the inclinedline ACfcos `i=OC/AC'; is the angle of elevation at B. between the horizontal BO and the lline of'sight BA and sin =AO/AB; 01 is the horizontal angle between the line OD and the line OCvand sin 01=DC'/OC; finally 02 isthe horizontal angle between the line BO and the line BC'andtan 02=DC'/BD. The relationship Aof rthe angle02 with respect tothe other three 'angles mayfbe expressed asfollows:

' cos a sin sin 01 sin a cos`/3l-cos a sinv cos Q1 Ifiiow the dipole interim-ais energized by a transmitter anda vertical loop'antenna'is located at B,

` y tari then thecbearing obtained eitherbyl the maximum` or minimum method will be thebearing Aof the pointC," and` not .ofthe point 0,'due to the effect of electric fleld. In otherrwords the bearing on a target as represented. by point C is thus determined directly without reckoning from the position of the radio a datum point. y

l Further consideringthe theoretical aspectsinvolving the signal energy at ythe point of reception, theinduced voltagel in the loop of a direction 'nderfcan be shown'to be the sum ofthe voltages induced. by three components of the ele'ctrostaticfeldat the direction finder, namely, due to the vertical iieid component, the horizpn'tai field component ,in the vertical plane of .propagation, and, the `horizontal fieldjcomponent at right angles tothe last'named component. When the direction lnderY loopl at B is so .rotated that a' line perpendicular to the. plane of the loopextends to point C, .then the voltages induced in the loopdu'e tothe vertical and horizontal eld components in the `vertical plane Iiriwhich lthe transmitter and direction finder lie balance the voltage inducedby the horizontal veld component perpendicular to the above vertical plane.

Referring to Fig. 8the angle 62 indicates the p oint C which is'thelpoint at which the theoretically'v extended antennafreaches the ground, or

the horizontal'plane inwhich the 'receiver loop4 lies. 'If,r.thlerefore,'a rigid yantenna is directed or pointed l'ongitl'idinally,l byy means of a sighting device' orientedalong or parallel to such' antenna, when the `Sighting device' indicates the target for example, at point.'C,"then` if asignal or signals be transmittedl during thefsighting interval, a directiolnL finder or Several directionfnders would obtain the bearingor bearings not of the radio transmitter andthe aircraft which carries said transmitter, but the bearing orbearings ofpoint Cwhich is the target. n

..In carrying` out lthel invention it is essential that a radiating antenna be provided which may be visually alignedby ,the4 observer with the longitudinal axis dir cted toward'the vobject or targetand inA a plane passing vertically through observation point and target. vA practical structhe non-Vernon, polarization ofthe radiated,

transmitter yand its antenna asy tural fembodmentis shawninyliligg-B. In; this instance :aririgid rdipole: antenna` asgat 1 4is :mounted in operative relation :withf a rtelescopic' sighting device 2- :In orderjathatrithefsightingdevice22 may be :maintained in parallelism with antenna l, mechanical lcoupling);means analogous to that of'a pantographfarezprovidediwhich comprise es-` sentially a1 connecting hfroid 3 `:and link f4, of insu-v lating material. A-Sighting. device 2 isypivotally mounted at the upper end of rodr3 ras a t5, and pivotally connected asat` ;Grto: link 4. The rigid dipole antenna 1 is pivotally mounted at the lower end. of rody as at'- andiisinsulated at its median p ointof pivotal connection withrod 3. Said j rod 3 is tubular "andgpreferably:.streamelined, and is mounted in bearings :8 andi 9 to swing -aboutits vertical axis; 'I fheantenna l isoperativej` with ag radio `-transmitter 10 "through feeder wires 11 and l2-which connect-through apair of brushes 1-3 and 1.4 twithcorresponding'fslip ringsl and 16 :whichare carried onrod andrproperly insulated therefrom. A- wirellead `1 .'7 is introduced into rod `3 whichis preferably f tubular, andis then electrically connectedto the` radiating arms of the dipole antennaaszat 1 118 1and 19.` Bearings 8v It should benotediinmpassing thatthe` slight difference. inheight ofthe optical axis of` the sighting device in` relationI tothe longitudinalfaxis of a rigidtform of. antennais negligible when considered in relationto the"` height of the aircraft and distance from the direction nders and causes no appreciable error.` i Y i Obviously, the" type O tantenna isnot limited to a dipole, .but otherforms of, rigid antenna may be employedwith egual success. For example, as shown in Fig. .4.; a rigid quarter ,wave antenna 1 maybe attachedin laiman'ner' similarto that shownin Fig. 3 sojasto'be rotatable aboutrod-S i `pended ina manner'similarto ajcatenaryand as a Vertical axis, which rod] also. carries at its upperlend a telescopicsighting device, 2 pivoted as at 5 and.maintainedin parallelismwith the antenna 1 by theY same pantog'raphici coupling means afforded byflinklfiofbakelite or other insulating material. As before the sighting device 2 and antenna'l'l maydoe swung in azimuth about the vertical axisof rod 3'; which rodl iis mounted in bearings 8 and= 9 attachedutofthe `fuselage o1 an airplane. In thisinstance the antenna l is `fed from theradio transmitter througha `feeder 'wirell from the antenna postfthrough brush 13 and slip ringv 15, whieh isfcofnnected! by a lead to the. conductive portion ,ofthelantenna T hemctal body or otherrnetal Astructureof` the `craft serves as a counterpoise, connection from the ground post ofthe set beingthroughlead12.

The principles fof theinvention also apply to a trailing antenna and such va formf of antenna is shown in Figs.V 5 and 6. Where atrailing antenna isused, it is well known] thatthe antenna is susthat thefantennawill hang more nearly vertical weight,the shorter-the antenna, andthe slower the speed of theaircrat...As` the current inthis type ot antennaisI greatest ati-,he lead rend ,and

trailingend, theformhf thempper part fofsuch antennais most Aimportant so far as radiation is concerned,` and the directional effect is closely thatwhichlwould be obtainedfrom a rigid antenna parallelto the.upper part of the wire and i having an anglebelowgthehorizontal asindicated -Where a rigid formi of ,antenna lis used, {tlie practical operation of the system may be followedby referencetol-Fifgs. 1,'2,;3 and 4 and `willbe brieflyA outlinedrasfollows: YThe `aircraft having visually `locatedthe' target theobserver merely trainshis `sighting device 2 on' thetarget, it being understood that in so doing therigid antenna 1 is 'maintained automatically with its longitudinal axis in parallelism'withLthe lineof'sight or optical axis of device.2, andin aplane passing vertically through `the ltarget and observation point. ln practice a warning signal would first he sentI so thatthe direction nderstations vwould be alert to receive andinterpret 'a specifiedlong dash signalor asuccession of signals to follow. It is only necessary thatrtheabove described relation ot sighting device, antenna and target be maintained during the interval that .specified signals i are being transmitted in order that the range and positiongof the target maybe accurately determined. Thus'the aircraft may take up any numberof convenient` positions out of the zone of anti-aircraft re in time of war, and not immediately above the object ortargetI as heretofore required by conventional-practice. i i

Inasmuch as such a trailing antenna cannot be oriented except by maneuvering the aircraftso that the antenna will :trail 4-in the longitudinal planefotthe craftfitis necessary toV provide a sighting device which inpractice is sc placed that its optical axis may begmaintained Aparallel vwith the Vlongitudinal` axis @f the airplane' body. `The sightingdeviceforconvenience may be made rotatable about a horizontal axis and suitable means of adjustmentlisgprovided sidthat the device maybe orientediin'altitude. Such arsighting device is, shown in Fig. -7 attached to the side of an gairplaneiuselagef and i includes a manual ladjustment in: altitudesuchas handwheel 22 and a' set screw 23 is provided to retainthe sighting device 2in-adjusted position. `In practice, where astandardtrailingwire antenna ofvdennite 4size and length;v is used, the telescopic sighting device must be set fortheair speed; theairplane is then flown toward thetarget until it is assured that on turning. and- 1 lyh away from. the target a line of sight above the target `beobtained; the airplane is then-reversed and lo wn -,directly away .i from the target in levelfflight. Whenthe` target appears in the telescopic sight of the sighting device, previously-adjusted as aforesaidv a signal is transmittedand the direction nders, whose attentiorrfmaybe assured by-va warning signal, will obtain1the-bearing o-fthe target with respectto be' aligned withV the upperor eiective radiating portion of such atrailing antenna longitudinally thereof and in a planelpassingvertically through observation point and target atthe time of' transmitting theysignals. i Y

. :Befertrinanow 11e-Figi?.- truenortli .isalorie .the

f ground. v

line B Nj If a direction'nnderat v13 hasits bearing scale oriented in such a manner that 'north is zero, then the true bearing of the line B D will be the angle' qb, and the: true. bearing vof the line B C Will be gt4-02 for. ql, which Willbe theA bearing obtained byf'the directicnnderif C is the trace or the point on the. ground at which .the dipole antenna at A- if 'extended would: reach the SimilarlyFig. 10 shows the bearing obtained if the direction nnderscalevis oriented with `respect to'a denit'e-base line B Blin such manner that a bearing in thei direction B1 is 180. Insuch case, the' bearingobtaine'd will be the'bearing of the pointI C, namelyk/ which is equal to p2-P02. Ifa seccnd"direction nder is now located at thepoint B1.` as `shown inFig. 11, and its scale is similarly oriented, then the bearing p4 will be obtained.4 ItWill be obvious;v therefore, that if C is a target its position'can be-readily traced on a map by laying 01T the tv/o'bearings, for ex- 'ample With respect to a baseline' BB1, or'by automatically indicating such bearing onal map by beams of "light remotelyi'controlled by the. tWo direction iinders at corresponding points B B1V on the ground. i

Furthermore, as shown in Fig. l2, abattery -at E can be layed to irelon such a target by obtaining the bearing of the. target at C with respect to the battery at E,

Changes and modifications are contemplated Within the scope and spiritofthe invention, as defined by the appended claims: vIclaim: Y

1`. A system of the'character described, comprising radio signalling means 'and including an antenna for radiating signal energy, said antenna being placed at an observation point in Avisual rangeofA an object and having a directional characteristic When-'its longitudinal axis is in alignment with said object; means including an adjustable sighting element for determining when the antenna is in longitudinall alignment with the objectand in a plane passing vertically.y through observation point andobject;r and meansr at a station or'station's remotely located Yfromsaid object to indicate a bearing on the object, said means including a bearing coil responsive to a component of the signall energy'having-a directional relation to said'object lWhentransmitted during the periodjof such alignment. A

2. A system'of the characterdescribed, ycomprising radio signalling means. located at an observation point in -visual range 'of an object, rand including an'antenna for radiating signal' energy to a station or stations bey'ondthe *visual range of the object; means lfor determining when the antenna is aligned longitudinally withA the object and in a plane passing'vertically through observation point and object, said meansincluding a sighting lelement adjustable in relation tothe antenna and the object; and 'means 'at the 'stations including a bearing coil to indicate a bearing on the object from avdirectional component'ofth'e signal energy passing Vthrough the objectand transmitted during the period vof such alignment.

3. A system-'of controlling ordnance nre from an aircraft operated inl'visual range'of a target,j

and in radio communication with direction finding stationsiradio'signalling' means carried 'by the craft iortransmitting modulated wave energy to said stations,` and'including an antennarfor radiating said Wave energy, said antenna having a directional characteristicin relation to the target when its effective' radiating portion is'longitudinallyin alignment fwith saidr target; means including 'an adjustable. sighting elementior determining VWhen the. antenna L is in longitudinal alignmentV with the ftargetiand, in a plane passing vertically through observation point andtarf Wave energy to stations :out of visual range of said target; means fordetermining the range and po` sition' ofv the target Without reckoning i fromv the position of 'l the rldio"transmitter 'as adatum point, said means includingan antenna operative Withftheftransmitterhaving a directional characteristic in relation* to'said target when its longitudinal axis is in optical alignment with the target'and in a plane passing'vertically through observation point and* target; means yfor determining ythe conditionl of alignment, Vcomprising a sighting element` adjustable inrelationvto antenna and target; and direction finding means at said stations including'afbearing'coil to obtain a bearing on the targetfrom" a directional component of the-,Waveenergy tremsrnitted during the period'ofsuch alignment.m I

l5. A system of v"controllingordnance fire from an observation pointfin visual range of av target; meansfat vthe observation vpointV comprising a radio transmitter for transmitting lmodulated wave energyv to a station or "stations out of visual range of said4 targetj means for vdetermining the range and position ofvthetargetl Without reckoning lfrom 'the-position: of the transmitter as a datum point, saidA means including a' rigid anthe range ofoadjustment'; and'direction finding means at saidstations including a bearing coil to obtain a bearing on theltarget from the directional component of the Wave energy transmitted during the period of such yalignment.l y

6'; A systemof' controllingordnance re from an aircraft operated 'in `v isualrange of a target, 'and in radiocommunication Withdirection iinding stations located'out of 'visuali range of said target; radio signalling lmeans carried by' the craft for transmitting" modulated wave energy to saidst'ations, v,and includinga rigid antenna adjustable iny relation, to' the target, ,said antenna having adir'ectional,characteristic in `relation to said target when its longitudinal axis isin optical valignment with the target and in a plane passing through observationpoint and target; a sighting elementoperative with the antenna for observingthe target j' means for adjustingsaid element inv altitude andazimuth; means for'maintaining .the'longitudinal jaxis of the antenna in parallelism With" the optical axis o f said element throughout the range of adjustmentand means at said stations including ajbearing coil for lobtaining bearings on the ytarget from' a' component y of said wave energy havinga directional" relation e to the target when transmitted during theY period of such alignment.

employs radio signalling apparatus located at an observation point in` visual range of an object, said apparatus including an antenna/to radiate modulated Wave energy to direction finding stations; the method which comprises the step of visually aligning the antenna longitudinally in a plane passing vertically' through observationy point` and object; transmitting a signal Wave during the period of such visual aligmnent; and deducing the position of the object at the direction iinding` stations from a directional component of such signal energy transmitted While the condition of alignment is maintained.

8. A systemof the character described, comprising radio signalling means located at an observation point in visual range of an object and including a radiating antenna for transmitting signal energy to stations beyond the visual range of said object; a sighting element for visually de- "i termining when said antenna is aligned longitu- 'radio signalling means, including a radiating andinally in a plane passing vertically through said observation pointfand said object; means to adjust said element to orient the observed optical axis in` `parallel relation with the longitudinal axis of the` antenna; and means at said stations for obtaining a bearing on the object from a directional component of the signal energy transmitted during the period of said alignment;

9. In a system of controlling ordnance fire from an observation point invvisual range of a` target, and employing radio signalling means comprising a radiating antenna for sending a modulated` Wave to radio direction nding stations; the method -of control Which;comprises the step of visually aligning the antenna longitudinally in a plane passing vertically through observation pointand target; transmitting a modulated radio Wave at the instant of such visual alignment; and obtaining a direct bearingon `the target from the directional signal data received during the period `of such alignment at the direction finding sta-v tions. Y y i i 10. In a system oficontrolling ordnance fire from anY observingwaircraft operated in `visual range oi a target, said craftbeing provided with tenna `to establish radio communication "with direction Vfinding. stations; the method which comprises the. stepof visually determining from the craft when the antenna has its longitudinal r i i axis in optical alignment with the target and 7. In a system of the character described Which' in a plane passing vertically through observation point and target; transmitting a signal Wave during the time of 'such alignment to establish a directional relation between the target and the effective longitudinal axis of said antenna; obtaining a direct bearing on the target at the direction finding stations from a directional comlponent of the signal energy transmitted While maintaining said parallel relation.

l1. In a system'of controlling ordnance fire from an aircraft operated in visual range of a target, said craft being provided With means including a radiating antenna to establish radio communication Withdirection nding stations; the method of control whichcomprises the step of visually determining from the craft when the effective longitudinal axis of the antenna is in optical alignment with the target and in a plane passing through observation point and target; transmitting a modulated Wave during the time i of visual alignment to establish a directional relation between the optical axis and the effective longitudinal axis of the antenna; and obtaining a bearing on the target at the direction iinding stations from a directional component ofthe signal energy received lat the time of such alignment.

l2. A system of controlling ordnance re, which employs an aircraft operated inl visual range of a target, and being rin radio communication with direction finding'stations; radio signalling means carried by the craft for transmitting modulated Wave energy to said stations, and including a rigid antenna adjustable in relation to said target, said antenna having a directional characteristic in relation to said target when its longitudinal axisis in optical alignment vwith the target and in a plane passing through observation point and target; a sighting element for visually determining when said antenna is aligned longitudinally in a plane passing Vertically through observation point and target,Y including means to adjust said element to orient the observed optical axis in parallelism with the longitudinal axis of said antenna; and means at the 

